March 11 (Reuters) - Britain's Financial Conduct Authority on Wednesday said it has blocked payment services firm Sendsii Ltd from carrying out any regulated activity after the company lost its tax authority registration.

Sendsii must return all funds held for customers and cannot conduct any regulated activity without the regulator's prior written consent, the FCA said.

(Reporting by Raechel Thankam Job in Bengaluru; Editing by Vijay Kishore)